My old White Knight gas tumble dryer played up the other day and I found
that the earth electrode (immediately above the main electrode) had eroded
and sagged until it was touching the central electrode. I bent it back and
all was well (briefly - but that's another story).

I thought I ought to order a new electrode but White Knight tell me that my
type (with integral earth electrode) has been superceded by one without an
earth electrode.

I'm sceptical that this will work in my machine (in the absence of an earth)
but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Tim

In article ,
"Tim Downie" writes:
My old White Knight gas tumble dryer played up the other day and I found
that the earth electrode (immediately above the main electrode) had eroded
and sagged until it was touching the central electrode. I bent it back and
all was well (briefly - but that's another story).

I thought I ought to order a new electrode but White Knight tell me that my
type (with integral earth electrode) has been superceded by one without an
earth electrode.

I'm sceptical that this will work in my machine (in the absence of an earth)
but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

Looks exactly like the ignition electrode in my Keston boiler.
They failed as the earth electrode drooped and the gap became too big
(it's mounted up the other way in the boiler's downward pointing burner).
They then modified them, and so far, the new type has been OK (I can't
remember what changed - I think the ceramic sleeve became longer, but
it still has the two electrodes).

I did repair the old ones a couple of times by bending the electrode
back, but this has to be done with it hot - if you try bending it cold
after it's had lots of heat treatment in the boiler, it's brittle and
usually snaps.

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Usually, the contact gap is resonably critical for proper ignition;
too small or big reduces chance of successful ignition (and too big
can also damage the spark coil). So it depends what the ground
electrode will be and how far away it is.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:
In article ,
"Tim Downie" writes:
My old White Knight gas tumble dryer played up the other day and I found
that the earth electrode (immediately above the main electrode) had eroded
and sagged until it was touching the central electrode. I bent it back and
all was well (briefly - but that's another story).

I thought I ought to order a new electrode but White Knight tell me that my
type (with integral earth electrode) has been superceded by one without an
earth electrode.

I'm sceptical that this will work in my machine (in the absence of an earth)
but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

Looks exactly like the ignition electrode in my Keston boiler.
They failed as the earth electrode drooped and the gap became too big
(it's mounted up the other way in the boiler's downward pointing burner).
They then modified them, and so far, the new type has been OK (I can't
remember what changed - I think the ceramic sleeve became longer, but
it still has the two electrodes).

I did repair the old ones a couple of times by bending the electrode
back, but this has to be done with it hot - if you try bending it cold
after it's had lots of heat treatment in the boiler, it's brittle and
usually snaps.

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Usually, the contact gap is resonably critical for proper ignition;
too small or big reduces chance of successful ignition (and too big
can also damage the spark coil). So it depends what the ground
electrode will be and how far away it is.

It's not an ignition electrode, it's for flame sensing (hence subject!).

Tim

On Sep 9, 2:05*pm, "Tim Downie" wrote:
My old White Knight gas tumble dryer played up the other day and I found
that the earth electrode (immediately above the main electrode) had eroded
and sagged until it was touching the central electrode. *I bent it back and
all was well (briefly - but that's another story).

I thought I ought to order a new electrode but White Knight tell me that my
type (with integral earth electrode) has been superceded by one without an
earth electrode.

I'm sceptical that this will work in my machine (in the absence of an earth)
but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Tim

There will be two electrodes. One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)
It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.
If it's old, it may have a different flame sensor which is a
thermocouple device. You can tell if it has this, there is a pilot
light.

harry wrote:
On Sep 9, 2:05 pm, "Tim Downie" wrote:
My old White Knight gas tumble dryer played up the other day and I
found that the earth electrode (immediately above the main
electrode) had eroded and sagged until it was touching the central
electrode. I bent it back and all was well (briefly - but that's
another story).

I thought I ought to order a new electrode but White Knight tell me
that my type (with integral earth electrode) has been superceded by
one without an earth electrode.

I'm sceptical that this will work in my machine (in the absence of
an earth) but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Tim

There will be two electrodes.

Well yes, I know that.

One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)
It's possible one electrode is used for both purposes.

Um no, not in this case. There is a seperate flame detector elctrode.

Or the two
electrodes may be identicle.
If it's old, it may have a different flame sensor which is a
thermocouple device. You can tell if it has this, there is a pilot
light.

Pilot light in a tumble dryer? I think not. ;-)

Anyway, for anyone who is interested, the technical bods from Crosslee have
been on the phone and tell me that as long as the tip is within 22mm of the
base of the burner, it will work without the earth electrode. Seems a
little odd given that the old gap was 1-2 mm. I'm not in a hurry to change
the electrode now though seeing as it's working.

Tim

On Sep 9, 7:56*pm, "Tim Downie" wrote:
harry wrote:
On Sep 9, 2:05 pm, "Tim Downie" wrote:
My old White Knight gas tumble dryer played up the other day and I
found that the earth electrode (immediately above the main
electrode) had eroded and sagged until it was touching the central
electrode. I bent it back and all was well (briefly - but that's
another story).

I thought I ought to order a new electrode but White Knight tell me
that my type (with integral earth electrode) has been superceded by
one without an earth electrode.

I'm sceptical that this will work in my machine (in the absence of
an earth) but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Tim

There will be two electrodes.

Well yes, I know that.

One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)
*It's possible one electrode is used for both purposes.

Um no, not in this case. *There is a seperate flame detector elctrode.

Or the two
electrodes may be identicle.
If it's old, it may have a different flame sensor which is a
thermocouple device. *You can tell if it has this, there is a pilot
light.

Pilot light in a tumble dryer? *I think not. ;-)

Anyway, for anyone who is interested, the technical bods from Crosslee have
been on the phone and tell me that as long as the tip is within 22mm of the
base of the burner, it will work without the earth electrode. *Seems a
little odd given that the old gap was 1-2 mm. *I'm not in a hurry to change
the electrode now though seeing as it's working.

Tim- Hide quoted text -

- Show quoted text -

Heh. No more dangerous than running a tumble dryer on gas in the first
place.

harry wrote:
On Sep 9, 7:56 pm, "Tim Downie"

Pilot light in a tumble dryer? I think not. ;-)

Anyway, for anyone who is interested, the technical bods from Crosslee have
been on the phone and tell me that as long as the tip is within 22mm of the
base of the burner, it will work without the earth electrode. Seems a
little odd given that the old gap was 1-2 mm. I'm not in a hurry to change
the electrode now though seeing as it's working.

Tim- Hide quoted text -

- Show quoted text -

Heh. No more dangerous than running a tumble dryer on gas in the first
place.

I'll bet many more house fires have been caused by electric dryers! ;-)

Seriously though, there are so many failsafes I doubt very much that a gas
dryer is any more dangerous than an electric one.

They certainly seem to be more durable. 21 years old and still going
strong.

Tim

In article ,
Tim writes:
harry wrote:
On Sep 9, 7:56 pm, "Tim Downie"

Pilot light in a tumble dryer? I think not. ;-)

Anyway, for anyone who is interested, the technical bods from Crosslee have
been on the phone and tell me that as long as the tip is within 22mm of the
base of the burner, it will work without the earth electrode. Seems a
little odd given that the old gap was 1-2 mm. I'm not in a hurry to change
the electrode now though seeing as it's working.

Tim- Hide quoted text -

- Show quoted text -

Heh. No more dangerous than running a tumble dryer on gas in the first
place.

I'll bet many more house fires have been caused by electric dryers! ;-)

Seriously though, there are so many failsafes I doubt very much that a gas
dryer is any more dangerous than an electric one.

They certainly seem to be more durable. 21 years old and still going
strong.

My first experience with tumble driers was a gas one (in my university
hall of residence). Full washing load dry in 5 minutes (and that was
probably after a spin at no more than 500RPM in top loading washer).
Also used similar ones in the US more recently.
Just have to be careful to check no one's melted a pair of trainers
in them beforehand.

Electric ones were a tremendous disappointment when I first tried one.
That's why I've never owned one.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 10 Sep,
Tim wrote:

I'll bet many more house fires have been caused by electric dryers! ;-)

Seriously though, there are so many failsafes I doubt very much that a gas
dryer is any more dangerous than an electric one.

They certainly seem to be more durable. 21 years old and still going
strong.

My first lasted about that long. (Support spider for drum failed, If I'd
known I could get one at the time it would have been repaired). It was
replaced by an almost identical one. Both White Knight.

Their service/spares dept is excellent in my experience.

--
B Thumbs
Change lycos to yahoo to reply

In message
,
harry writes
On Sep 9, 2:05*pm, "Tim Downie" wrote:
My old White Knight gas tumble dryer played up the other day and I found
that the earth electrode (immediately above the main electrode) had eroded
and sagged until it was touching the central electrode. *I bent it back and
all was well (briefly - but that's another story).

I thought I ought to order a new electrode but White Knight tell me that my
type (with integral earth electrode) has been superceded by one without an
earth electrode.

I'm sceptical that this will work in my machine (in the absence of an earth)
but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Tim

There will be two electrodes. One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)

Good job I got back in time ...

No Harry, stick to your solar panels, you are completely wrong

It ABSOLUTELY doesn't measure the resistance, a flame acts like a lossy
rectifier and the flame sense circuit is looking for that rectification
effect in the flame - its a very safe way of flame detection since it
depends on a parameter that can't easily be duplicated in the way that a
resistance can

As long as the jet from which the gas issues is well earthed, then there
is a circuit when there is a flame (assuming that the sense electrode is
also in the flame)



It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.

But this isn't the case, is it? he said so

If it's old, it may have a different flame sensor which is a
thermocouple device.

No - he's shown the old one as a single electrode, not a junction

You can tell if it has this, there is a pilot
light.

Eejit


--
geoff

On Sep 18, 11:04*pm, geoff wrote:
In message
,
harry writes





On Sep 9, 2:05 pm, "Tim Downie" wrote:
My old White Knight gas tumble dryer played up the other day and I found
that the earth electrode (immediately above the main electrode) had eroded
and sagged until it was touching the central electrode. I bent it back and
all was well (briefly - but that's another story).

I thought I ought to order a new electrode but White Knight tell me that my
type (with integral earth electrode) has been superceded by one without an
earth electrode.

I'm sceptical that this will work in my machine (in the absence of an earth)
but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Tim

There will be two electrodes. *One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)

Good job I got back in time ...

No Harry, stick to your solar panels, you are completely wrong

It ABSOLUTELY doesn't measure the resistance, a flame acts like a lossy
rectifier and the flame sense circuit is looking for that rectification
effect in the flame - its a very safe way of flame detection since it
depends on a parameter that can't easily be duplicated in the way that a
resistance can

As long as the jet from which the gas issues is well earthed, then there
is a circuit when there is a flame (assuming that the sense electrode is
also in the flame)

It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.

But this isn't the case, is it? he said so

If it's old, it may have a different flame sensor which is a
thermocouple device.

No - he's shown the old one as a single electrode, not a junction

You can tell if it has this, there is a pilot
light.

Eejit

--
geoff- Hide quoted text -

- Show quoted text -

I wish you'd just **** off. I was repairing and running industrial
gas equipment for forty years.
http://en.wikipedia.org/wiki/Auto_reignition
http://en.wikipedia.org/wiki/Flame_d...lame_detection

In message
,
harry writes
On Sep 18, 11:04*pm, geoff wrote:
In message
,
harry writes





On Sep 9, 2:05 pm, "Tim Downie" wrote:
My old White Knight gas tumble dryer played up the other day and I found
that the earth electrode (immediately above the main electrode) had eroded
and sagged until it was touching the central electrode. I bent it back and
all was well (briefly - but that's another story).

I thought I ought to order a new electrode but White Knight tell
me that my
type (with integral earth electrode) has been superceded by one without an
earth electrode.

I'm sceptical that this will work in my machine (in the absence of
an earth)
but I could be wrong.

Here's what mine looks like.

http://www.zen31010.zen.co.uk/images/ffe.jpg

The replacement is just the same but without the "hockey stick" earth
electrode.

I'm waiting to hear from the technical adviser at the moment.

Should I just try it or is my scepticism justified?

Tim

There will be two electrodes. *One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)

Good job I got back in time ...

No Harry, stick to your solar panels, you are completely wrong

It ABSOLUTELY doesn't measure the resistance, a flame acts like a lossy
rectifier and the flame sense circuit is looking for that rectification
effect in the flame - its a very safe way of flame detection since it
depends on a parameter that can't easily be duplicated in the way that a
resistance can

As long as the jet from which the gas issues is well earthed, then there
is a circuit when there is a flame (assuming that the sense electrode is
also in the flame)

It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.

But this isn't the case, is it? he said so

If it's old, it may have a different flame sensor which is a
thermocouple device.

No - he's shown the old one as a single electrode, not a junction

You can tell if it has this, there is a pilot
light.

Eejit

--
geoff- Hide quoted text -

- Show quoted text -

I wish you'd just **** off. I was repairing and running industrial
gas equipment for forty years.


And you were prolly as incompetent then as you are now. I have vastly
more experience on modern domestic gas appliances than you do

It's not industrial gas equipment, is it - we're talking about modern
domestic gas appliances here. They don't use UV / IR , they rarely use
thermocouples (and if you had a clue, it would be obvious from the
sketch that it wasn't)

http://en.wikipedia.org/wiki/Auto_reignition
http://en.wikipedia.org/wiki/Flame_d...lame_detection

This "One implementation of a gas burner with auto reignition senses the
electrical conductivity of the flame."

and this " There are also ionisation flame detectors, which use current
flow in the flame to detect flame presence, ... " while not incorrect,
are misleading and written by someone who doesn't understand the
process - I do

Flame sense electrodes (in modern domestic gas appliances) work on
detecting a rectification effect produced by the flame, they do NOT work
on resistance

for example

http://contractingbusiness.com/feature/cb_imp_13002/

"Flame rectification has become the primary means of flame sensing in
virtually all new residential and commercial gasfired HVAC equipment.
The days of the mercury filled autopilot and bimetal warp switch are
long gone. Be it an intermittent pilot system, direct spark ignition, or
a hot surface system, manufacturers have chosen flame rectification for
their means of flame verification.

Why flame rectification? It may be the safest form of flame sensing
available. It's virtually impossible to fool the ignition module with
anything short of an actual flame simulator. It's very fast, with no
cool down time such as with a thermocouple or autopilot. The gas flow
can be stopped almost instantaneously. Any sensing circuit failure will
result in a system shut down rather than an unsafe ignition."

So - you can **** off with your outdated and inaccurate claptrap. Half
of your input to the thread was wrong, the other half (thermocouples and
such) was just irrelevant


--
geoff

t may be the safest form of flame sensing available. It's virtually impossible to fool the ignition module with anything short of an actual flame simulator
Thx Geoff, helpful to a novice as a start point for reading up on this.

--
For full context, visit https://www.homeownershub.com/uk-diy...on-729526-.htm